Turbo machine



' T. VON KARMAN ET AL March 29 1927. 1,622,930

TURBO MACHINE Filed Aug. 21. 1924 2 Sheets-Sheet 1 W M! Era/1m By: W

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March 29-, 1927.

'r. VON KARMA ET m.

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Patented Mar. 29, 1927.

I UNITED STATES 1,622,930 PATENT OFFICE.

THEODQR von KARMAN, or AACHEN, GERMANY, AND xAnL'rnoMM, or ALLnN'rowN,

PENNSYLVANIA.

TURBO MACHINE.

Application filed August '21, 1924, SeriaI No. 733,418, and in GermanyOctober 8, 1921.

screws, etc. and also turbo power machines which convert the energy in afluid into mechanical energy, such machines being for example water andsteam turbines, air motors etc.

The invention consists in building up each of some or all of the bladesof a turbine in sections divided by gaps that are adapted to give riseto collateral currents which carry the main current of fluid along withthem and prevent the main current from leaving the blade surface. Theblade sections may be assembled on dilferent circular members which maybe adapted to be displaced with respect to each other. The bladesections are so constructed that when the gaps between neighbouringblade sections are closed a continuous or connected blade contour isformed of each series of associated blade sections on the sides of lowerand higher pressure when the sections abut upon each other so as toclose the intervening gaps. The regulation of said gaps may beaccomplished in any suitable manner, as by hinged or sliding gaps or byturning the rings with. their blade sections relatively to each other.

The invention is shown by way of example in the drawing in which- I Fig.1 is a section through two adjacent blades of the rotor of a turbocompressor while Fig. 1 is a radial sectionthrough the rotor.

Fig. 2 is a section similar to Fig. 1 except that each of the blades isdivided into several instead of only two sections) Fig. 3 is a speeddiagram of the blade arrangement of Fig. 1.

Fig. '4: shows a blad arrangement in which the blade sections arearranged on concentric circular members, Fig. 4? showing thecircular'members of Fig. 4 displaced with respect to each other so asto' form gaps between the blade sections belonging toeach blade.

Fig. 5, shows a development of the blades of an axial turbine.

In accordance with Figs. 1 and 1 the blades are generally constructed sothat at a certain speed of revolution and at a certain output thefluid'enters the rotor without any shock occurring between the fluid andblade. This is illustrated in Fig. 3 in which the speed '11), relativelyto the rotor is the resultant of the speed a, at which the fluid passesradially through the machine and of the speed of revolution 11,. But ifthe output or quantity of fluid delivered by the machine is reduced, asby a throttling device, the relative speed w, in relation to the radialdirection will form a greater \angle which would result in a lossthrough shock. Consequently the pressure which could be obtained bymeans of the compressor without this loss will be reduced. A furtherincrease of the angle 0: will even result in the current'of fluidleaving the blade, which becomesnoticeable during operation of themachine by a sudden drop of head. These drawbacks are overcome by theinvention by sub-divid ing the blades a, c in blade sections a, b, b, 0as shown in Fig. 1 It, with this arrangement, the angle grows, a part ofthe air or fluid passing through the machine will rush through the gapsb,- b and prevent the shock and divert the entire current so that itwill follow the form of the blade or contact therewith up to the point aBy this means a greater rise of pressure, particularly in the case ofsmall outputs, is obtained. A further advantage of the arrangement isthat in consequence of the current of fluid being caused to contact withthe blades under different operating conditions. the number of bladescan be reduced, so that a saving of materialanda reduction of lossesthrough friction results. By increasing the pressure in turbocompressors the number of steps in the same can also be lessened.

As shown in Fig. 2 eaehblade may be subdivided into several sections a,b, I), o, 0, (Z, d, 6 with interveninggaps b, b, 0, c, 03, d.

In the modification shownin Figs. 4 and 4 each blade is divided into twosections. the smaller sections being attached to a circular carryingmember and the larger sections being attached to a second circularcarrying member. The circular members I, 11 may be fixed relatively toeach other or they may be arranged to be displaced relatively to eachother during operation as in dicated in Fig. 4 such displacementenabling regulation of the machine. In many cases it is advantageous toarrange the blade sections so that in a certain position of the rotatingcircular members the gaps-b, 6, etc. are completely closed andassociated blade sections form a single more or less smooth blade asshown in Fig. 4.

Another modification consists of an axial turbine with blades spacedcomparatively far apart as in modern high speed machines. Fig. 5 shows adevelopment of the blade system for an axial turbine. In this figure thespeeds in relation to the rotor, which is imagined to be stationary, areshown. WVhen the fluid enters the machine running at its normal speed ofoperation without shock, the current passing into the machine when itruns at a reduced speed will form an obtuse angle or with the initialtangent of the blade so that the current will tend to leave, or tearaway from. theconvex side of the blade and this will give rise to areduction of output or etliciehcy. In accordance with the invention theblade system is subdivided so that the fluid thatpasses through the gapsb, b regulates the total current in such a way that, even when thecurrent entering the machine deviates still further from the angle atwhich normallyno shock arises, the current will contact properly withthe blade so that the second or third section Z), c, c, (i will becomeeffective, which would not be the case if the current were to tear awayor leave the blade. By displacing the various series of blade sectionsI, II, III a regulation can be obtained which is as good as thataccomplished by turning the individual blades and which is far simplerin structural. design. Instead of regulating the gaps b, b, c, 0', etc.,by turning the circular blade section carriers, the same result may beobtained by closing the gaps by hinged or slidable members or any othersuitable device. The blade sections could also be rotated.

The invention may be applied in a similar manner to rotary pumps, screwventilators,

wind wheels, steam turbines, etc.

o claim 1. Inturbo machines, blades co-operating with the fluid passinghrough the machine, each of said blades being made with uniformcontinuous contours at either sides of its body and having comparativelysmall gaps provided therein whereby said blade is divided into sections,said gaps being adapted to pass a con'iparatively small portion of thefluid from one side of the blade to the other one and to so produceauxiliary streams to draw the main stream between two blades unto andalongside of the contour or the respective blade, said blade sectionsdivided being carried by'circular carrying members.

2. In turbo machines, blades co-operating with the fluid passing throughthe machine, each of said blades being made with uniform continuouscontours at either sides of its body and having comparatively small gapsprovided therein whereby said blade is into sections, said gaps beingadapted to pass a comparatively small portion of the fluid from one sideof the blade to the other one and to so produce auxiliary streams todraw the main stream between two blades unto and alongside of thecontour of the respective blade and said blades being formed ofadjustable blade sections adapted to be positioned to dividesaid bladesby producing the aforesaid gaps.

3. In turbo machines, blades co-operating with the fluid passing throughthe machine, each of said blades being made with uniform continuouscontours at either sides of its body and having comparatively small gapsprovided therein whereby said blade is divided into sections, said gapsbeing adapted-to pass a comparatively small portion of the fluid fromone side of the blade to the other one and to so produce auxiliarystreams to draw the main streams between two blades unto and alongsideof the contour of the respective blade, the blade sections beingadjustable to vary the widths of the aforesaid gaps. 4. In turbomachines, blades co-operating with the fluid passing through themachine, each of said blades being made with uniform continuous contoursat either sides of its body and having comparatively small gaps providedtherein whereby said blade is divided into sections, said gaps beingadapted to pass a comparatively small portion of the fluid from one sideof the blade to the other one and to so produce auxiliary streams todraw the main stream between two blades unto and alongside of thecontour of the respective blade, adjustable gaps being produced bymaking said sections movable.

5. In turbo machines, blades co-operating with the fluid passing throughthe machine, each of said blades being made with uniform continuouscontours at either sides of its body and having comparatively small gapsprovided therein whereby said blade is divided into sections, said gapsbeing adapted to pass a comparatively small 'portion of the fluid fromone side of the blade to the other one and to so produce auxiliarystreams to draw the main stream between two blades unto and alongside ofthe contour of the respective blade, said sections being made adjustableso as to form at will in the closed position a single smooth blade, orin open position one divided by gaps.

6. In turbo machines, blades co-operating with the fluid passing throughthe machine.

each of said blades being made with uniform cont1nuous contours ateither sides of its body and having comparativelysmall gaps providedtherein whereby said blade is divided into sections, .said gaps beingadapted to pass a comparatively small portion of the fl'uidfrom-one sideof the blade to the other one and to so produce auxiliary streams todraw the main stream between two blades unto and alongside of thecontour of the respective blade, said bladesections being carried bymembers adapted to be arranged in adjustable spaced relation to oneanother so as to have at will a blade subdivided by ga s or closed intoa continuous single bla e, said carrying members corresponding in numberto that of the sections in'a blade and each carrying one and the sameparticular section of each blade.

In testimony whereof we tures.

THEODOR VON KARMAN. KARL FROMM.

